Abstract: Ampicillin-sulbactam combination is the most frequently prescribed antibiotic in diabetic foot ulcers. We conducted a retrospective study to evaluate the antibiotic sensitivity of bacteria isolated to this antibiotic. In 33 patients with diabetic foot ulcer (September 2008-March 2009), 67% were culture positive in which Citrobacter spp accounted for 36% of these isolates. The rest isolated included Pseudomonas aeruginosa (22%), Proteus spp (18%), Acinetobacter spp (9%), Klebsiella pneumoniae (5%), Escherichia coli (5%) and Staphylococcus aureus (5%). These isolates were more likely to be ampicillin-resistant (n=18) than were ampicillin-sensitive isolates (n=4). Ampicillin resistance has raised our concern about current practice of prescribing ampicillin/ sulbactam as monotherapy for majority of our patients with such ulcers.